SQRT[Z*Y] = SQRT [[Z11 + jZ12]*[Y11 + jY12]] = Z11*Y11 - Z12*Y12
+jZ12*Y11 +jY12*Z11 [I think I got all the terms correct.]

So, the attenuation constant is still a complex number and it is
dimensionless.

In the transmission line equations the attenuation constant is
multiplied by line length yielding an expression in Nepers
[dimensionless] and radians [dimensionless].
Cecil Moore wrote:

Dave wrote:

Alpha and Beta got transformed into ? and j?. Gamma also got
transformed into ?.


Now it makes more sense. :-) What is scarey is that some
browsers may display Greek characters correctly and some
may not.

What kind of bait are you throwing out about SQRT[Z*Y] ?


Z is the distributed series impedance and Y is the distributed
shunt admittance. The equation for the propagation constant
is gamma = alpha + j*beta = SQRT(Z*Y). Doesn't multiplying
an impedance by an admittance result in a dimensionless
quantity?